1. Field of the Invention
The present invention relates to automatically plucking the strings of a stringed instrument. More specifically, it relates to automatically plucking strings that are being automatically fretted so that more than one note is sequentially sounded on a given string. Even more specifically, it relates to an actuating arm driven by a motive device operable for automatically plucking a string of a stringed musical instrument.
2. Description of Related Art
Mechanically automated musical instruments have been in use for some time, and percussion instruments such as pianos, accordions, drums, marimbas, cymbals, etc., as well as wind instruments such as organs and calliopes have traditionally been the object of automation, while the automation of stringed instruments presents a unique challenge to be discussed in detail, below.
The means for automation has evolved with changing technology. For example, for well over a century automated pianos known as player pianos have used a pneumatic actuator, sometimes called a "pneumatic", to strike a piano key when a hole assigned to that key is sensed in a moving paper tape known as a piano roll. The piano roll has a series of holes corresponding to the notes of the piano which are to be played, and one can change piano rolls in order to change songs. The piano roll is made to pass over a tracker bar which has a row of holes corresponding to all of the possible hole positions across a single row on the piano roll. Coincidence of any piano roll hole passing over a corresponding tracker bar hole causes a respective pneumatic to depress a piano key. The use and operation of such player pianos is well known and described for example in the present inventor's prior U.S. Pat. No. 4,619,177 issued Oct. 28, 1986, entitled MUSICAL INSTRUMENT PNEUMATIC ACTUATOR, and hereby incorporated by reference.
With the advent of the computer and a musical instrument digital interface, termed "MIDI", the roll can be replaced by instructions stored in the computer memory. The instructions cause electronic signals to be sent over a data cable between a MIDI connection located in the computer and a corresponding connections located in the instrument. The MIDI connection includes an electronic communications protocol for translating computer instructions and data into specific channels directed to each instrument to be automated, and further directed to each note to be sounded in a particular instrument. MIDI connections are commonly used to operate electronic instruments such as an electronic piano, wherein the notes are produced by signals synthesized and shaped to reproduce musical sounds through a sound system. In the case of player pianos and other automated acoustic instruments, i.e., instruments other than electronic keyboards, the signals received at the instrument end cause each pneumatic to be turned on and off, as appropriate to the desired music. As discussed in the present inventor's co-pending patent application Ser. No. 08/932,380, entitled MAGNETIC VALVE SYSTEM, and hereby incorporated by reference, the traditional piano roll and the alternative MIDI interface each have their benefits and drawbacks, some of which determine subtle characteristics of the musical sound produced by the instrument.
Turning to the more difficult task of automating of a stringed instrument, a satisfactory means for automating the sounding of the strings of a stringed musical instrument has eluded manufacturers of automated musical instruments, regardless of the means for storing the recording of the notes to be played, i.e., paper tape or MIDI-based computer memory. While the strings of all stringed instruments have pre-set lengths and tensions and are either struck or plucked, the strings of some instruments such as the non-pedal harp and the dulcimer are sounded simply by respectively plucking and striking the string as it is found, while the sounding portion of the strings of guitars and banjos is often simultaneously shortened by pressure against the string, while the string is being sounded. In such instruments, the neck of the instrument, which is located beneath the strings, provides a flat surface against which the musician can individually press each string at a selected location along the length of the string, so that the sounding portion of the string is shortened to achieve a desired note. This procedure, sometimes referred to as "fretting", temporarily shortens the portion of the string that is free to vibrate after the string is plucked. The sound produced by the vibrating string can be allowed to continue for a desired length of time, after which the pressure holding the string against the surface of the neck is released and another position on either the same or a different string is selected and pressed, so that another note can be sounded when plucked.
Inherent to the automation of any instrument is the requirement that the instrument be available to operate without human operation. A separate, but important condition is that the instrument should not require frequent tuning.
Put differently, when simply turned on, the automated instrument should reproduce music adhering to desired standards of tone, tuning, and other parameters particular to the type of instrument and style of music being played. As is commonly known, whenever departure from such parameters occurs, the resulting music is likely to fall short of the listener's expectations and pleasure, e.g., the notes sound "sour" or "tinny", etc. Consequently, while control of all of the parameters described herein is not essential to a rudimentary automated stringed musical instrument, the quality of music reproduction produced by the instrument strongly relates to which parameters are controlled and how that control is achieved.
One such parameter is the maintenance of proper tension in the strings, i.e., the stringed instrument must remain "in tune". As is commonly known, stringed instruments rarely retain their tuning for extended periods of time for a variety of reasons, including the selection of materials used for construction of the instrument and the design of the instrument, as well as the temperature and humidity of the surrounding environment each the time the instrument is played. Musicians typically assess the tuning of the strings at the start of each day's playing and once having tuned the instrument, typically have to readjust the tuning over a period of several hours as tension in the strings continually changes away from the initial setting. Accordingly, while an automated stringed musical instrument can be effective for a period of time without automatic maintenance of the desired tuning point of each string, such automatic tuning is a necessity for achieving quality musical sound over a substantially long period of time.
In a typical instrument, the tension in a string is set in response to rotation of a respective shaft that is rotationally mounted at one end of the string, and is arranged so that the string wraps around the shaft so that the string becomes tensioned by rotation of the shaft.
It is therefore a principal object of the present invention is to provide an automated means for individually plucking each string of a musical instrument.
Another object of the present invention is to provide an automated means for individually fretting each string of the musical instrument to shorten the sounding portion of the string.
A still further object of the present invention is to provide an automated means for individually maintaining a pre-set tension in each string of the musical instrument over substantially long periods of time.